Field of the Invention
The present invention relates to an image pickup apparatus that automatically generates a time-lapse moving image, a moving image generation method, and a storage medium.
Description of the Related Art
An example of image pickup apparatuses such as a digital camera is provided with a time-lapse photographing function, a time-lapse moving image generation function, an automatic bracket photographing function (specifically, an automatic exposure (AE) bracket photographing function or an automatic focus (AF) bracket photographing function) and the like. The time-lapse photographing function is a function to perform photographing a predetermined number of times every predetermined set time. The time-lapse moving image generation function is a function to generate a moving image from photographed images which have been sequentially acquired using the time-lapse photographing function. The AE bracket photographing function is a function to acquire a plurality of photographed images by performing photographing under a plurality of exposure conditions in photographing of a single frame. The AF bracket photographing function is a function to acquire a plurality of photographed images having different focus positions in photographing of a single frame.
In general, these functions are arbitrarily set according to a subject or a photographing condition by a user of the image pickup apparatus, and for example, a setting is assumed in which a plurality of frame images are requested to be acquired in combination with the AE bracket photographing function at the time of photographing of a single frame using the time-lapse photographing. With respect to such a request, a technique is proposed in which photographing of a single frame in which multiple exposure photographing with a predetermined exposure time is performed arbitrary number of times is repeatedly performed for a predetermined number of times with a predetermined time interval (see Japanese Laid-Open Patent Publication (Kokai) No. H11-212139).
According to the technique disclosed in Japanese Laid-Open Patent Publication (Kokai) No. H11-212139, for example, it is possible to acquire a plurality of photographed images with a plurality of differences in exposure level using an AE bracket photographing function in every photographing of a single frame in photographing of a plurality of frames. However, when the photographed images are used as a frame image in the photographed order in the case of generating a time-lapse moving image from the photographed images acquired as mentioned above, a moving image in which a change in brightness and darkness are repeated is formed. In order to avoid this problem, the user needs to sort the photographed images for each difference in exposure level, which makes the operation troublesome.